Error Updating 'Addon'

[naddral]

I keep gettibg the error message: 'Error Updating 'Addon': sun.security.validator.ValidatorException: PKIX path building failed..........

I can't read anymore but there seems to be a lot more info.
I know its a certificate issue, but where do I change it. There are no other error messages that come up apart from the one within minion.

[Shirik]

I have heard of this issue before but I'm still having trouble tracking it down. Are you behind a proxy or do you have any other kind of strange network setup?

[naddral]

No mate, just bog standard network setup. Using virgin media broadband connection and kaspersky security software.